Chlorowax-naphthalene condensation product pour depressant for middle distillate fuels



United States Patent CHLOROWAX-NAPHTHALENE CONDENSATION PRODUCT POUR- DEPRESSANT FOR MIDDLE DISTILLATE FUELS William E. Lifson, Union, and William C. Hollyday, Jr.,

Watchung, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed June 8, 1962, Ser. No. 200,919

3 Claims. (Cl. 44-62) This invention relates to a product formed by condensing a particular kind of chlorinated wax with naphthalene in a prescribed Friedel-Crafts reaction to make the condensation polymer product a more potent pour depressant in petroleum middle distillate oils, such as heating oils and diesel fuels.

The middle distillate fuels are obtained as straight run and cracked petroleum oils which boil in the range of about 350 F. to 800 F. These oils are between kerosene and lubricating oils in volatility. A low pour point is requiredof any middle distillate fuel which is to be pumped or otherwise transferred at low temperatures. Ingeneral, pour points as measured by the well-known ASTM method have been found to be more reliable than filterability tests in indicating the minimum temperature at which these fuels can be used. In practical application, filters are (or can be) warmed soon after equipment start-up, and any wax crystals present in the fuel flowing to the filter melt and cause no trouble. However, if the pour point is too high and the fuel will not flow at the beginning, the equipment cannot be started.

It is also well known that the pour point is a good indication of the lowest operating temperature for a lubricating oil. Pour point depressants best adapted for lowering the pour points of lubricating oils have been made for many years by condensation of certain chlorinated waxes with naphthalene. The optimum composition of the reactants and the optimum reaction conditions have been discovered through research over a long period of time; but now, in accordance with the present invention, critical changes in the condensation product, particularly with respect to the kind of chlorinated wax reacted, have been discovered to make a product better adapted to and more potent for depressing the pour point of middle distillate fuels.

US. Patent 2,297,292 of G. H. B. Davis et a1. describes the general method for making a pour point depressant effective for heavy oils, particularly lubricating oils, by Friedel-Crafts reaction of a chlorinated wax, preferably a high melting point wax (ca. 140 F. M.P.) chlorinated to contain preferably to chlorine.

The critical requirements which distinguish the synthesis and composition of the pour depressants which are effective in middle distilates, as made in accordance with the present invention, are:

(A) Description of the wax.The paraifin wax should have a melting point in the range of 97 to 113 F., preferably 100 to 108 F., as determined by the ASTM method. This kind of wax is principally composed of normal paraflins which distill within the range of 370 to 470 F. under 10 mm. Hg absolute pressure.

(B) Description of the chlorinated wax.--The paraffin wax is chlorinated by known methods, but the chlorinated wax is made to contain 18 to 22 wt. percent chlorine.

(C) Reactant ra!i0.ln the Friedel-Crafts (AlCl catalyzed reaction), 330 to 675 parts by weight (preferably 333 to 665 parts by weight) of the chlorinated wax are used per 100 parts by weight of the naphthalene to form the reaction mixture.

The criticality of these requirements were demonstrated by many tests with control of the variables as shown in the following representative examples:

Example 1 Chemically pure normal eicosane (ii-C H with a melting point of 97 F. was chlorinated to 14 wt. percent chlorine by passing a stream of chlorine gas into the melted paraffin at 195 to 205 F. I

This chlorinated parafiin (111 g.) was condensed with 13.1 g. of naphthalene in the Friedel-Crafts reaction to give 60 g. of polymeric product. The solvent was 44 ml. of o-dichlorobenzene, the catalyst was 2.5 g. of anhydrous aluminum chloride, the temperature was 100 to 120 F and the time of reaction was about 5 /2 hours. Unreacted wax and chlor-owax were extracted from the product with warm methanol (recovered 48 g.).

The pour depressant activity of this material in a typical middle distillate heating oil is shown in Table II.

Example 2 The n-eicosane was chlorinated as in Example 1, but to a higher chlorine content of 26 wt. percent.

Example 3 This is similar to Example 1 except a commercial highly n-paraflinic wax of 116 F. melting point was chlorinated to 14 wt. percent chlorine.

Preparative details of the Friedel-Crafts condensation product with naphthalene are given in Table I, and pour depressant activity is illustrated in Table II.

Examples 4 and 5 These are similar to Example 1 except a commercial highly n-paraifinic wax of 123 F. melting point was chlorinated to 14 wt. percent and 18 Wt. percent chlorine, respectively.

Preparative details of the Friedel-Crafts condensation product with naphthalene are given in Table I, and pour depressant activity is illustrated in Table II.

Examples 6 to 13 (Examples according to this invention) Preparative details of the Friedel-Crafts condensation products with naphthalene are given in Table III, and pour depressant activity is illustrated in Tables IV, V and VI.

In Examples 6 and 7, the n-eicosane described in Examples 1 and 2 was used. In Example 8, the wax was a commercial highly n-paraffinic wax of- 100 F. melting point, 99% of which distilled in the range of 366 to 425 F. and in the range of 382 to 411 F.

The wax was chlorinated to 20 wt. percent chlorine and this chlorinated wax was condensed with naphthalene similar to Example 1.

In Examples 9 to 13, a n-paraffinic wax of 108 F. melting point was chlorinated to five different percentages of chlorine under the same conditions as for the n-eicosane in Example 1. Before chlorination, 99% of this Wax distilled between 264 and 485 F. at 10 mm. Hg pressure and 90% distilled between 407 and 470 F. at that same pressure.

TABLE I.PREPARATION OF WAX/NAPHTHALENE M.P. of Percent G. Cl Wax/ G. Product/ Example N0. Wax, I C1 in 01 g. Naphtha- 100 g. Naph- Wax lene thalene (None of these examples falls within the claims of this invention.)

TABLE II.-POUR DEPRESSANT ACTIVITY OF WAX/NAPH- THALENE 1 Pour Point, F., Using Product From- Wt. Percent Product Exam- Exam- Exam- Exam- Example 1 ple 2 plc 3 ple 4 plc 5 Total Lowering 2 80 45 85 80 90 t 1 In a mixed straight run/cracked heating oil of the following descripion:

Pour Point 0 F.

+8 F. 2.24 cs./100 F. API Gravity 32.7 F. Distillation Range- 346 to 628 I 2 Total lowering is the sum of the differences between the pour point of the heating oil without the pour point depressant additive and the pgur rgig t of the heating oil after adding each of five concentrations of e a 1 we.

TABLE III.-PREPARATION OF WAX/NAPHTHALENE M.P. of Percent G. 01 Wax/100 G. Product] Example No. Wax, F. 01 in 01 g. Naphtha- 100 g. Naph- Wax lene thalene (Examples 6, 7 and 13 are on the border of the scope of this invention.)

1 In the heating oil described in Table II.

TABLE V.-IOUR DEPRESSANT. ACTIVITY OF WAX/NAPH- THALENE 1 Pour Point, F., Using Product From- Wt. Percent Product Example Example Example Example Total Lowering 60 55 115 115 1 In a straight run middle distillate of +10 F. pour point, +12: F' cloud point, 2.35 cs./100 F. viscosity, 371 AII gravity, 354 to 624 F. distillation range, and 148 F. anlllne point.

TABLE VI.-POUR DEPRESSANT ACTIVITY OF WAX/NAPH- THALENE 1 Pour Point, F., Using Product From- Wt. Percent Product Example Example Example Example Total Lowering 15 10 130 140 1 In a cracked middle distillate of +20 F. pour point, +28 F. cloud point, 3.62 cs./ F. viscosity, 225 API gravity, 408 to 660 F. distillation range, and 109 F. aniline point.

The observed data, as illustrated in the foregoing tables, has proved that there is a specific relationship between the kind of chlorinated wax condensed with, a naphthalene and the effectiveness of the condensation product in a particular petroleum oil with respect to its boiling range. For effectiveness in the middle distillate oils which boil in the range of 350 F. to 800 F., the wax which is chlorinated should be principally straight chain or normal paraflinic wax having a melting point in the range of 97 F. to 113 F., preferably 100 F. to 108 F., and the chlorine content of such chlorinated wax should be in the range of 18 to 22 wt. percent, preferably from 19 to 21 wt. percent, with an optimum of 20 wt. percent. The ratio of the chlorinated wax reactant to the naphthalene is significant also in obtaining a most effective pour depressant for the middle distillate oils, which may be straight run petroleum fractions, cracked petroleum fractions, or a mixture of straight run and cracked petroleum fractions boiling Within the specified middledistil-late oil boiling range. These pour point depressants are preferably to be added in a small proportion of about 0.01 to 0.20 wt. percent to the middle distillate fuels for imparting the desired improvement in lower pour point. Such fuels requiring improvement generally have a pour point above about -l0 F. without the presence of a suitable pour pointdepressant. The four point depressants of the present invention are suitable for use in middle distillates having pour points between -10 F. and +30 F. and are particularly efiectivc in middle distillates having pour points between 0 F. and +20 F.

The pour points were determined for three different middle distillates or gas oils in which the condensation products were added in concentrations of 0.01, 0.02, 0.03, 0.05 and 0.10% by weight. The total lowering of degrees F., obtained by adding the individual lowerings at each concentration, did not exceed 90 for Examples 1 to 5, whereas the totals for Example 11, the optimum according to the present invention, were 175, 115 and in the three gas oils. Total lowerings of 115 minimum are generally characteristic of the performance of the pour point depressants of the products of the present invention.

The invention described is claimed as follows:

1. A composition of a middle distillate petroleum fuel oil blended with a small amount of about 0.01 to 0.2 Wt. percent of a chlorinated Wax-naphthalene condensation polymer for lowering its pour point, said middle distillate petroleum oil boiling in the range of 350 F. to 800 F., said condensation polymer being a product synthesized by reacting 100 parts by weight of naphthalene with 330 to 675 parts by weight of an n-paraffin waxcontaining 18 to 22 wt. percent chlorine in the presence of AlCl catalyst, the said wax unchlorinated having an ASTM melting point of 97 F. to 113 F.

2. A composition of a middle distillate petroleum fuel oil blended with a small amount of about 0.01 to 0.2 wt. percent of a chlorinated wax-naphthalene condensation polymer for lowering its pour point, said middle distillate petroleum oil boiling in the range of 350 to 800 F., said condensation polymer being a product synthesized by reacting 100 parts by weight of naphthalene with 330 to 675 parts by weight of an n-paraffin wax containing 19 to 21 wt. percent chlorine in the presence of A101 catalyst, the said wax unchlorinated having an ASTM melting point of 100 to 113 F.

3. A wax-naphthalene condensation polymer of increased effectiveness as a pour depressant in a middle distillate petroleum fuel oil, said polymer consisting essentially of the condensation reaction product synthesized by reacting 100 parts by weight of naphthalene with 330 to 675 parts by weight of a chlorinated n-paraflin wax conaluminum chloride as catalyst, said wax unchlorinated having an ASTM melting point of 97 F. to 113 F.

References Cited by the Examiner UNITED STATES PATENTS 2,015,748 10/ 1935 Frolich 260-671 2,125,875 8/1938 Barnard 4457 2,174,246 9/ 1939 Lieber et a1. 260671 2,177,732 10/ 1939 MacLaren 4480 2,297,292 9/1942 Davis et a1. 260-671 2,688,643 9/1954 Dean et a1. 260--671 2,773,915 12/1956 Baker et al 260671 taining 18 to 22 wt. percent of chlorine in the presence of 15 DANIEL E. WYMAN, Primary Examiner. 

1. A COMPOSITION OF A MIDDLE DISTILLATE PETROLEUM FUEL OIL BLENDED WITH A SMALL AMOUNT OF ABOUT 0.01 TO 0.2 WT. PERCENT OF A CHLORINATED WAX-NAPHTHALENE CONDENSATION POLYMER FOR LOWERING ITS POUR POINT, SAID MIDDLE DISTILLATE PETROLEUM OIL BOILING IN THE RANGE OF 350*F. TO 800*F., SAID CONDENSATION POLYMER BEING A PRODUCT SYNTHESIZED BY REACTING 100 PARTS BY WEIGHT OF NAPHTHALENE WITH 330 TO 675 PARTS BY WEIGHT OF AN N-PARAFFIN WAX CONTAINING 18 TO 22 WT. PERCENT CHLORINE IN THE PRESENCE OF ALCL3 CATALYST, THE SAID WAX UNCHLORINATED HAVING AN ASTM MELTING POINT OF 97*F. TO 113*F. 